diff --git a/pkg/dev_compiler/lib/src/analyzer/module_compiler.dart b/pkg/dev_compiler/lib/src/analyzer/module_compiler.dart
index 570a7c5..3b09257 100644
--- a/pkg/dev_compiler/lib/src/analyzer/module_compiler.dart
+++ b/pkg/dev_compiler/lib/src/analyzer/module_compiler.dart
@@ -174,7 +174,7 @@
 
   /// *deprecated* If specified, `dartdevc` will synthesize library names that
   /// are relative to this path for all libraries in the JS module.
-  final String libraryRoot;
+  String libraryRoot;
 
   CompilerOptions(
       {bool sourceMap = true,
diff --git a/pkg/dev_compiler/web/web_command.dart b/pkg/dev_compiler/web/web_command.dart
index 31008db..ac2b54f 100644
--- a/pkg/dev_compiler/web/web_command.dart
+++ b/pkg/dev_compiler/web/web_command.dart
@@ -141,6 +141,7 @@
     var summaryData = SummaryDataStore([], resourceProvider: resources);
     var compilerOptions = CompilerOptions.fromArguments(argResults);
     compilerOptions.replCompile = true;
+    compilerOptions.libraryRoot = '/';
     for (var i = 0; i < summaryBytes.length; i++) {
       var bytes = summaryBytes[i];
 
@@ -253,7 +254,7 @@
         sb.write('import ${json.encode(existingLibrary)};\n');
 
         for (var import in unlinked.imports) {
-          if (import.uri == null) continue;
+          if (import.uri == null || import.isImplicit) continue;
           var uri = import.uri;
           // dart: and package: uris are not relative but the path package
           // thinks they are. We have to provide absolute uris as our library